Paradichlorobenzene block



March 26, 1968 F, E. BATTON PARADI CHLOROBENZENE BLOCK Filed Sept. 17, 1964 PAPDICHLORO- scEmme AGENT MIXER swczmo MACHINE HEAT 'TBEATME NT BELOW |27F m BLOCK CENTER.

FINISHED BLOCK.

INVENTOR FRAA/c/s ,6. BATTOM ea mw WK ATTORNEY 5 United States Patent ()fi 3,375,159 Patented Mar. 26, 1968 3,375,159 'PARADICHLOROBENZENE BLOCK Ih'ancis' 'E. Batton, New Martinsville, W. 'Va.,' assignor to Pittsburgh Plate Glass Company,*Pittsburgh, Pa.,a=cor- :porafion of Pennsylvania Filed Sept. 17, 1964, Ser. No. 397,296 5 Claims. (Cl. 167--30) ABSTRACT OF THE DISCLOSURE A method of improving'the strength of scented paradichlorobenzene blocks or cakes is described in which the :p'aradiclilorobenzene block or cake containing the Lscentingagent is passedthrough a heat source-and 'hea't- .ed to a temperature and 'for a period of time'sufiicient to coalesce the particles on the surface of the .block'or cake =without deforming it. Specifically the heatttreatment is conducted .at such temperatures. and forperiods of time s'uflicient to preventtthe blockifrom achieving a temperature of :127 F. in the center thereof. Various methods of heating the block .are described. 'Aspecific example on-electrical heating is shown.

The present inventionrelateszto a'metho'd of improving the strength 'of scented, compacted crystals of paradiparadichlorobenzene packet of compressed crystals having a pleasant odor. In conducting this scenting process the liquid perfumeor-scenting material is mixed withthe paradichlorobenzene crystals prior to compressing them into the desired physical form. Afterthorough mixing of the crystals with thescenting agent, theorystals are then compacted or compressed to the desired shapein apressing machine by applying suitable pressure to the scented crystals-in a die. Typical'ptressures are from 300to 2,000 p.s.l.

One disadvantage encountered in scenting orperfuming paradichlorobenzene crystals which are made'intocakes or blocks has been that the finished product loses a considerable-amount of'its normal strength due tothe'presence of the perfume .or scenting materials. All perfumes .employed for this purpose have this eife'ct'on the finished product to a. greater or lesser degree. The net result of the employment of these materials in 'paradichlorobenzene compressed crystal bodies is the same however, their normal strength, that is, the strength of the compressed crystal bodies without such perfumes, is markedly re duced. Thus, it is quite common for a *finished paradichlorobenzene block not containing any scented material to have a breaking pressure on the .order of '700 to 800 p.s.i..thefirst day after manufacture. A similar blockcon- 1 taining a'scenting material will have a breaking pressure of something on the order of 200 to 300 p.s.i. In the ,.shipping and handling of the finished blocksor cakes of .scented paradichlorobe'nzcne, considerable breakage is "thus encountered."While the presence of scenting ma- ,,terials in ,paradichlorobenzene blocks is a desirable feature in reducing the unpleasant odor of unscented crystals of paradichloroben'zene and imparts a pleasantodor for certain applications, for example, as sanitary cakes for toilet bowls, for deodorizing closets, etc. the decreased strength of such scented materials and the subsequent breakage detracts from their desirability.

In accordance with the instant invention a method has been devised whereby ,paradichlorobenzene cakes'may be ,formed with the scenting material :and a considerable reduction in the loss of strength normally encountered readily achieved. In accordance with the present invention paradichlorobenzene crystals are admixed with the scenting materials to be employed. After the scenting material has been thoroughly mixed with the paradichlorobenzene crystals, the crystals are compacted in a conventional manner and then contacted with a heat source at a high enough temperature and for a sufiicrystals to coalesce or fuse at least on the surface of the block. In this manner a compacted mass of paradichlorobenzene is provided which maintains a high breaking strength for a considerable period of time, while surprisingly during the heating operation little or no Weight loss of'the paradichlorobenzene compacted crystals occurs.

When conducting the heat treating step of the instant invention recourse of various types of heat may be had. It is preferred that the heat be applied by an electrical source, preferably through the utilization of heat lamps or heating panels or other similar electrical devices. While this mode of heat application is preferred, other sources of heat may-be employed. Thus, heat supplied indirectly from gas fired furnaces, light sources, resistance wires,

and other'similar heating mechanisms may be readily employed. It would be undesirable of course 'to utilize. a heat source which directly impinged a flame on the para- -dichlorobenzene crystals and thus direct firing of the cakes with aflame is to be avoided.

The temperatures to which the paradichlorobenzene compacted crystals are subjected will vary considerably depending upon the length of time that it is desired to expose the cake or block to the heat source. Generally, temperatures may range between 'F. up to about 200 F. It is preferable in applying heat to the compacted crystals of scented paradichlorobenzene that the heat be applied in the range ofbetween about F.-and

about ;l75 F. The total quantity of heat applied to the block during treatment should be ofcourse below that -which would cause deformation of the block by melting period of-time ranging bet'ween 60 seconds "to about 10 minutes.

It is found in=operating in accordance with the above parameters that panadichlorobenzene cakes which 'have been scented with perfumes will form a hard cakebav- :ingconsiderably more strength than a paradichlorobenzene scented cake which has not been heat treated. Surprisi'ngly the weight loss occurring during the heat treatment willnormally be about'one half of 1 percentof the :total weight of't'he block subjected'to the' heabtreatmen't.

Thus, the advantages gained byincreased'strengthgreatly :outweigh any weight loss as minute as those encountered during the heat treating steps herein set forth.

For a more complete understanding of the present invention, reference is made to the following example, which is illustrative with one mode of practicing the present invention.

Example While the invention has been described with reference tocertain specific examples, it is to be understood that it is not to be so limited except insofar as appears in the accompanying claims.

I claim:

1. A method of improving the strength of scented, compacted crystalline paradichlorobenzene comprising contacting said scented, compacted crystalline paradichlorobenzene with a source of heat at a temperature sufficiently high and for a period of time sufficient to cause the paradichlorobenzene crystals to coalesce at least on the surface but insuflicient to causethe temperature in the center of the block to exceed 127 F.

2. A method of improving the strength of scented, compacted paradichlorobenzene cake comprising contacting said cake with a source of heat at a temperature of between 120 F. to 200 F. for a period of time ranging from 30 seconds to 15 minutes but insuflicient to cause the temperature in the center of the block to exceed 127 F.

3. The method of claim 2 wherein the temperature ranges between 150 F. and 175 F. in a period of time ranging between 60 seconds to 10 minutes.

4. A method of improving the strength of scented paradichlorobenzene blocks comprising contacting said blocks of par-adichlorobenzene with a source of heat at a temperature of at least 165 F. for a period of at least 3 minutes but insufficient to cause the temperature in the center of the block to exceed 127 F.

5. A scented paradichlorobenzene block prepared in the manner set forth in claim 4.

The equipment used for the heat treatment was a 24 inch wide belt conveyor 14 foot in length, This conveyor was surrounded by an oven 24 inches wide and 12 foot in length. The oven was equipped with six, 16 by 24 inch Corning glass heating panels rated at 2500 watts and 230 volts. The panels were evenly spaced over the 12 foot length of oven and were mounted 2 /2 inches above the canvas conveying belt. For the heat treating test, the temperature in the oven was controlled at 19 165' F. by a rheostat on the power supply to the panels. The scented blocks of paradichlorobenzene 2.25 inches in diameter and 0.75 inch thick were placed flat on the conveyor and carried through the oven at a feed rate of 8 feet per minute. Since only one side of the block was treated this way, the blocks were then passed through the oven a second time and the unexposed side of the block was treated. The total exposure time was 3 minutes and the oven temperature was 165 F. None of the blocks treated in this manner were deformed in shape after treatment. Utilizing these procedures, a series of four runs were made on paradichlorobenzene blocks prepared by mixing 6 ounces of various commercial perfumes with paradichlorobenzene crystals and subsequently blocking these scented crystals in a blocking machine by compression. The blocks were sent through the furnace on the conveyor belt in the manner indicated above and upon completion of the exposure were tested for their breaking strength. The results of these tests are set forth in the table below. As a control to determine the effectiveness of the heat treatment, paradichlorobenzene blocks manufactured from the same perfumes and in the same manner as those treated above but not subjected to the heat treating step were compared for their breaking strength at intervals from 1 to 20 days. The results of these tests are shown below in Table II.

TABLE I Oz. Perfune/ Age of Block (days) Paradi- Compound chlorobenzene 0 1 2 3 4 5 10 15 20 Added Breaking Pressure (p.s.i.)

Felton Rose 1 6 350 400 420 475 450 M, MdzR Spice 1 6 300 325 400 340 Nerve, Pine 1 6 340 400 350 300 GdzD, Nectar Bouquet 6 330 300 580 660 450 1 Blocks annealed at 165 F. for 180 seconds.

TABLE II Oz. Perfune/ Age of Block (days) 100# Paradi- Compound chlorobenzene 0 1 2 3 4 5 10 15 20 Added Breaking Pressure (p.s.i.)

Felton Rose 6 275 M, M&R Spice 6 200 120 Narve, Pine 6 310 260 G&D, Nectar Bouquet 6 240 120 As can be readily seen from the examination of the GO Referen Cited two tables, the paradich'lorobenzene blocks which had been heat treated exhibited, immediately after treatment, sig- UNITED STATES PATENTS nificant increases in strength over those which Ho 1346537 7/1920 Real-k 167-30 receive any heat treatment, After a pfillOd Of one day 1515364 11/1924 Roar-k 167 30 th p i on shows an even greater difieren'ce between 65 2328690 9/1943 Steele 167-30 the two ets of scented blocks. 2789078 4/1957 Tllusler 167*33 As can be readily seen from the above results, by ex- 21081336 5/1937 Hmegardner 260*650 posinggcented aradichlorobenzene blocks to the heat 2527606 10/1950 Webb 260 650 treatment hereinabove described, superior scented para- 14 7/1958 Koury 264 X dichlorobenzene blocks are prepared which possess 70 strength qualities in this product heretofore not attain- ALEXANDER BRODMERKEL Pnmary Examme-r' able. P. E. ANDERSON, Assistant Examiner. 

